Advancing stem cells: New therapeutic strategies for treating central nervous system disorders

In this special issue, we explore new methods and knowledge to improve stem cell transplantation in diseases and conditions such as stroke, PD, and depression. Advancing the conventional idea regarding cell replacement in stem cell therapy, stem cells may also transfer healthy mitochondria to diseased ischemic neurons in stroke and improve the therapeutic time window of tissue plasminogen activator (tPA) in a conjunctive therapy for stroke, and human Wharton’sJelly-derived mesenchymal stromal cells (hWJ-MSCs) may rely mainly on trophic factor secretion to induce neuroprotective effects. In addition, trophic factors such as neurotrophin-4/5 (NT-4/5) and glial cell line-derived neurotrophic factor (GDNF) may enhance stem cell survival and differentiation to dopaminergic neurons for PD treatment, while encapsulating mesenchymal stem cells and GDNF-secreting cells may increase graft survival rates and their ability to promote neurogenesis and neurotrophic factor secretion in therapies for depression and PD. Of note, transfecting stem cells with a contrast agent such as a superparamagnetic iron oxide (SPIO) for tracking with magnetic resonance imaging (MRI) after transplantation may render these transplanted cells more vulnerable to toxicity in ischemic and hypoxic conditions. Moreover, other methods such as transient microglia depletion may protect against cosmic radiation-induced cognitiveimpairments, and focusing on the collaborative efforts between oligodendrocytes and the neurovascular unit cells to repair damaged white matter may improve therapies for white matter injury.